The overall objective of this project is to develop a microporous composite prosthesis that will be permanently incorporated by the host for use in segmental replacement of the trachea. Fabrication methods have been developed to reproduce the microporous exoskeleton of sea urchins and corals (Replamineform technique) with elastic polymers that can be reinforced with rigid rings and impregnated with a biodegradable material to provide a tight seal prior to bioincorporation. Testing of the experimental prostheses in the canine thoracic trachea has demonstrated that connective tissue ingrows Bioelectric Polyurethane but not silicone rubber in 120-180 microns (coral, Montipora) but not 18-25 microns (sea urchin, Heterocentrotus mammalatus). Thrombus vs. gelatin as biodegradable filler had no effect on ingrowth. Bioincorporation appears to be limited by infection. The next phase of the project will be to limit infection and promote complete bioincorporation of Bioelectric Polyurethane (pore size 120-180 microns) prostheses. Two methods will be tested: I. Bioincorporation in subcutaneous location prior to tracheal implantation and II. Incorporation of antimicrobial agents into the polymer and filler. Secondary means will include evaluation of thinner wall thickness to favor earlier bioincorporation and extended administration of systemic antibiotics. Experience with tracheal implants will be correlated with subcutaneous implants.